Patent Literature 1 describes an optical fiber cable to be laid in a microduct (thin tubular duct) by air blown installation. Patent Literature 1 describes that three tensile strength members are buried in a sheath at 120-degree intervals around a loose tube (tube housing a plurality of optical fibers with filler capable of stopping water).
Patent Literature 2 describes an optical cable housing, in a sheath, an optical fiber unit formed by wrapping a plurality of optical fibers with a wrapping tape. Patent Literature 2 describes that two tensile strength members are buried in the sheath in such a manner as to sandwich a housing part housing the optical fiber unit.